Adhesive tape



45 been introduced, there may also be incorporated glycol, di and trimethyl glycol and derivativessuch 45 '50 soluble gums, glass wool, synthetic tanning sub-' mixture of glycerine and dihydric alcohols ismore o Patented May 2,1939 I I I I 2,156,335'

UNITED STATES PATENT OFFICE I i I 2,156,335

ADHESIVE TAPE Leon W. Geller, Astoria, Long Island, N. Y., as- I signor, bydirect and mesne assignments of onehalf to Nelson J. Fonarow and one-half to Edward J. Carter, both of New York, N. Y.

No Drawing. Application July 8, 1936, Serial No. 89,664

1 Claim. (CI. 91-68) This invention relates to adhesive tapes. may be opaque, phosphorescent, luminescent,

Heretofore, the backing used for adhesive tapes perfumed, of higher tensil strength and which has been made either from cellulose, cellulosic postesses other new and desirable properties. material, or cellulose derivatives. Examples of The gelatine sheets, modified as indicated these are paper, Cellophane, cloth, etc. Cellulose, above, can be made waterproof by treating with as is well known, is a substance of vegetable origin solutions of potassium alum, or potassium chroand has a chemical composition which corremate,or chrom sulphate, or chrom alum, or chrom sponds to a polybasic alcohol which is free from chloride, or chrom Peroxide, with metallic nitrogen. salts of aluminum, iron, cerium, or by the action The p esent invention provides an improved of chlorine, or hypochloric acid, or with solution backing. or base'material for adhesive tapes which of orga c Substances, Such as of tannic acid. is of animal origin land has a different chemical chinon, phenols, naphtols, acetaldehyde, or other composition from that of cellulose and cellulose ehy s- T l e e pe may he derivatives. More specifically, the base material hardened by using f y e Which is One 16 of the invention is gelatine, a protein, which can of the most important hardening agents for gelaw be mixed with numerous materials to provide t e; nd which y e brought to act D the advantages and qualities not readily obtainable elatine sh t in vapor form, or if d s d. mixed heretofore in adhesive tapes. In accordance with with the ge ti mass in the presence of a the invention, one may obtain a drying or nonhardening retarder, Such as a, a then 20 drying tape, a water-soluble or water-insoluble cast and heated until hardened. 20 tape by applying adhesive compositions to gela The thus obtained flexible, modified and watertine sheets which have been previously modified p oo ha e d gelatine Sheets y now used 1 and hardened. For improving the properties of instead of paper, cellulose derivatives or cloth, as the tape, the gelatine can be mixed before or after a ase fo ad p its hardening, with various substances of inor- The adhesive compositions for the tapes may 25 ganic or organic origin. The products so obtained be water-soluble or water-insoluble, of drying or may thus be made to difier from the original non-drying type, and the finished product may material by newly acquired qualities, such as be a transpare t an p q ap a o ed opacity, color, tenacity and other new properties. or a phosphorescent or even a perfumed tape,

Since gelatine sheets are usually brittle, they depending not only on the kind of modified gela- 30 can be transformed into a very flexible. material t e which has b n use b also p e d through the use of plasticizers, such as glycerine, of adhesive which has been applied to the gelaalcohols, soaps, fats, sugar, sulphonated oils, sultine sheet. A clear, transparent resin adhesive phonated fats, borax-shellac solution, aliphatic willgive a transparent tape whereas a resin-rubdihydric alcohols and similar reacting substances.- ber adhesive will furnish an opaque tape.

The product so obtained is of'superior and satis- For the production of a transparent waterfactory flexibility and it may be further improved soluble non-drying or pressure sensitive tape, the by raising its viscosity through addition of subge at e S ee sv oa ed w th a Wateroluble stances like resins, sulphonated fats, sulphonated adhesive, such as water-soluble resins mixed with 40 fatty alcohols and other substances which may dihydric aliphatic alcohols, and glue mixed with 40 produce the same effect upon gelatine. This prowater-soluble resins and dihydric aliphatic alcocedure will produce a more or less transparent hols. Under the term dihydric aliphatic alcomaterial, but in the gelatine, which is ready to be hols, it is understood there fall diabasic alcohardened and in which placticizers have already hols, such as glycol, diethylene glycol, triethylene othersubstances for the purpose of changing the as esters and ethers. There are generally soluble appearance or improving the qualities of the in water and are of a higher hygroscopicity than original gelatine sheets. Such materials are dyethe vtrihydric aliphatic alcohols, for example, stuffs, resins, waxes, gums, starch, urea, waterglycerine. But, in many cases the glycerine or a stances, perfumes, hydrogenated fats and oils, aldesirable, due to the fact that they are less hybumen, casein, tannic acid, cork, sawdust, asbesgroscopical. tos, inorganic salts, leather, ammonium stearate, One manner of obtaining a water-soluble admetallic soaps and many other substances. Thus, hesive for a non-drying type of.tape is as fol- 1 one may obtain a sheet of various colors, which lows: The glue is first soaked in water until it swells, after which it is dissolved by heat in a steam jacketed kettle. To this is added, at a temperature of about 150 E, triethylene glycol, and the mixture stirred until a homogeneous mass is formed. Then a water-soluble adhesive resin is added, which will raise the viscosity of the mass in the same way as sugar will do. An example of the proportions which may be used is:

Parts Glue 1 Water 1 Dihydric aliphatic alcohols '2 to 4 Resins to 1 pose of balancing the qualities and properties of the adhesive compositions.

For the production of a transparent water-insoluble non-drying tape, the gelatine sheet is coated with a water-insoluble but transparent adhesive, such as adhesive-resins, for example, glyptal resins, vinyl resins. The resins are dissolved in a suitable solvent and, if necessary, modifled by a plasticizer, after which operation they are ready. to be applied on the tape.

The rubber adhesives are made from crepe or smoked sheets of rubber and resins or waxes, or with an admixture of both. By heating the rubber with resins and waxes, the rubber depolymerizes and forms adhesives. For the'depoiymerization of the rubber, there has .been used mostly synthetic resins, such as glyptals, urea resins, aldehydes, condensation resins, vinyl resins, although it has been found that the chlorinated wax resins, especially chlorinated paraflln' resins,

depolymerize rubber easily forming adhesives of very good qualities. especially to all the natural waxes, such as-scale paraflin, paraflin, beeswax, candelilla wax,'montan wax, carnauba wax. The chlorparaffln resins are obtained by chlorination of a paraflin solution. These last resins areoi various consistency, from balsam-like to veryhard, brittle resins, corresponding to the quantity of chlorine introduced in the paraflln. The waxes, it will be understood, of course, can also be chlorinated in the presence of other substances. 1

In a similar way, the rubber may be depoli- By the term "waxes I refer amount of resins and waxes necessary for the ity of the materials and on the depolymerization power of these two depolymerization agents. An example of how this may be done in practice is given merely for the purpose of exposition. In a mixer provided with heat, the rubber sheets are introduced and under good mixing, the rubber is heated until it is soft enough and able to incorporate resins and waxes. These substances are added in small quantities until a sample shows that the depolymerized rubber has the desired adhesive properties. The depolymerized rubber adhesive is then dissolved in benzol or other solvents and isready for application to the gelatine backing.

Previous to the application of the adhesive, the gelatine sheet may be covered, if required, on the surface to which the adhesive is applied, with a coating of waterproof or solvent-proof material, which will depend on'the kind of substances used as adhesives, and also on the degree of desired transparency of the tape. For rubber or any kind of opaque gelatine tape, a rubber coating is very desirable, not only because it will serve as a protective coating but also because these two different layers, namely gelatine and rubber, give a very good material for the production of tapes.

The rubber to'be applied isdissolved in benzol.-

In case of a transparent tape, the protective layer chlorinated rubber resin, which may be modified by a plasticizer.

Coatings made from chlorinated naphthalin .backing, an adhesive-on the treated side of said backing, and a coating obtained from a mixture of depolymerization will depend entirely on the qualcan be= a transparent resin, such as glyptal, or

a chlorinated naphthalin wax and chlorinated r rubber on theside of said tape which is free from said adhesive.

LEON W. GELLER. 

